Transcript Introduction - Blanche Ely High School

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Photosynthesis
Packet #16
Chapter #8
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Introduction I
 Photosynthesis
 The process of storing
light energy from the
sun in the form of
glucose
 The process of making
sugar (glucose) using
light energy
 Photo--”light”
 Synthesis--”make” ;
“put together”
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Introduction II
 Photosynthesis nourishes
almost all of the living
world directly or indirectly
 Autotroph
 Organism that obtains
organic food molecules
without eating other
organisms.
 Use energy from the sun
or from oxidation of
inorganic substances to
make organic molecules
from inorganic ones.
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Introduction III
 Heterotroph
 An organism that
obtains organic food
molecules by eating
other organisms or their
by-products
 Humans eating plant or
animal matter
 Fungi on feces,
carcasses
 Bacteria of the large
intestines
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Photosynthesis
Chemical Reaction
6CO2 + 12H2O + Light Energy --> C6H12O6 + 6O2 + 6H2O
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Structure of the Leaf
Site of Photosynthesis
 Chloroplasts are the sites of
photosynthesis in plants.
 Found within mesophyll cells.
 Chloroplasts contain chlorophyll
 A green pigment that captures
light energy during
photosynthesis
 Found in the cells of the
mesophyll of the leaves
 Stomata
 Pores under the leaves where
CO2 enters and O2 leaves the
plant/leaf
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Events of Photosynthesis
 The Light Reactions
 Photo part of
photosynthesis
 Calvin Cycle
 Synthesis part
 What does the plant
synthesize?
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Light Reactions
Light Reactions
 “Photo” part of
photosynthesis
 Convert solar energy to
chemical energy
 Contains the photo systems
that cooperate in the light
reactions of photosynthesis
 Each photosystem will
absorb specific wavelengths
of light


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Photosystem I--700nm
Photosystem II--680 nm
 Oxygen is formed in
photosystem II
 H2O is a reactant in
the formation of O2
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ATP & NADPH
 ATP is produced at
Electron Transport Chain
#1
 NADPH is produced at
Electron Transport Chain
#2
 ALL ATP and NADPH
produced during the Light
Reactions are transported
to the Calvin Cycle to be
used in the synthesis of
glucose
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Light Reactions I
Overall
 Inputs
 Light
 NADP+
 ADP
 P
 H2O
 Outputs
 ATP
 NADPH
 O2
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Cyclic vs. Non Cyclic
Electron Flow
Light Reactions—Non-cyclic Electron
Flow
Photosystem II
I.
a.
Electron Transport Chain I
II.
a.
ATP produced will be used
in the Calvin Cycle
Photosystem I
III.
a.
Continues the movement of
electrons
Electron Transport Chain II
IV.
a.
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The reaction center drives
an oxidation-reduction
reaction (Redox Reaction)
that helps in the formation
of oxygen.
NADPH produced will be
used in the Calvin Cycle
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Non-Cyclic Electron Flow
 Uses both photosystems
 Produces NADPH, ATP
and oxygen
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Cyclic Electron Flow
 Only uses photosystem I
and part of Electron
Transport Chain I
 Produces ATP but no
NADPH or O2
 Used to “make-up” the
necessary amount of
ATP’s for the Calvin
Cycle
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Calvin Cycle—The Dark
Reactions
Calvin Cycle
 “Dark Reactions”
 Synthesis of
photosynthesis
 Makes sugar
 Uses ATP and NADPH to
convert CO2 to sugar
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Calvin Cycle
Overall
 Inputs




CO2
H2O
ATP
NADPH
 Outputs




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Sugars (Glucose)
ADP
P
NADP+
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Calvin Cycle
Sequence of Events
 Carbon Fixation

Use of carbon dioxide
 Reduction
1, 3 bisphosphoglycerate is
reduced to the sugar G3P
 6 ATP’s is used


Reduced using the electrons
produced by the oxidation of
NADPH
 Regeneration of CO2 Acceptor

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This acceptor, RuBP, is then reused in carbon fixation to
continue the next cycle of the
Calvin Cycle
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Review